That means she can make a "tactical rounding". If the outside boat has right-of-way, then she need not give the inside boat anything more than "mark-room". That is pretty much (technically a little different but very similar to) room for a "seamanlike rounding".
Hi Eric -
In the Brad Dellenbaugh rules seminar, he warned that mark room does not entitle you to a seamanlike rounding. He said you get to go straight to the mark, that's it. No coming up for speed, maneuvering, etc... you get to sail "proper course" when you get to the mark, but for some distance (60 feet?) you're screwed. Monohulls might be able to pull off a mark-room rounding, but I think a cat in particular can get into a world of hurt inside the zone when "entitled" to mark room only. After the scenarios we explored during the seminar, I've been even more careful about the zone at the gate.
It might be differently interpreted by a cat-savvy judge, maybe? Interested in your take.